The present invention is directed to a branch connector for light waveguides which connector utilizes a beam divider principal. The connector comprises a pair of light waveguides on a common axis; a beam divider, which is arranged on a plane slanted to the common axis and extends between the ends of the waveguides which are flushed therewith, to reflect a beam traveling parallel to the common axis along a given direction, and at least one additional waveguide adjacent one of the pair of aligned waveguides on a second axis extending at an angle to the common axis and intersecting the common axis at the beam divider mirror with the second axis being oriented to extend along the given direction.
Branch connectors of the above mentioned type have already been proposed in optical communications for use as optical multiplexers and demultiplexers. These branch connectors have been proposed in various compact structural shapes which do not require lenses. Their characterstic features are the use of the beam divider principal with a spectrally selective beam divider mirror instead of the conventional beam divider mirror. It has turned out that in the case of the spectrally selective beam divider mirror with an angular radiation of incidence, the polarization effect occurs which becomes larger as the angle of incidence becomes larger. These polarization effects limit the channel spacing which is obtainable with the branch connector. Articles in IEEE Transactions on Communications, Vol. Com-26, No. 7, July, 1978, pages 1082-1087; Fiber Integr. Opt., 2, 1979, page 1, and Electronics Letters, Vol. 15, No. 14, July, 1979, pages 414 and 415, disclose the work of various Japanese groups which use complicated arangements with lenses and reduce the disturbing polarization effect by means of using almost perpendicular radiation incidence or radiation incidence of small angles.